Tuesday, February 28, 2006

The New Tourist's Guide to the Milky Way - space.com

The Irish novelist George Moore once wrote, “a man travels the world in search of what he needs and returns home to find it.”

Astronomers sometimes follow a similar philosophy when they want to learn about our galactic home, the Milky Way.

Because Earth is located on the same plane as the Milky Way’s disk, astronomers can’t look down upon our galaxy to study it the way they can for others, like Andromeda. So for a long time, even basic things about the Milky Way, such as its shape and size, were difficult to determine.

Fly Through ItWATCH VIDEO

Take a quick tour through our galaxy and beyond, with stops at major attractions!

Time travel

Astronomers came up with a variety of ways to solve this problem. They invented tools that see in ways human eyes can’t, devised clever measuring techniques, and, as Moore suggested, they “travel.”

With penetrating telescopes, astronomers roam the entire universe, exploring billions of galaxies in their virtual spaceships. They take the lessons, some of them learned billions of light-years away and billions of years back in time, and apply them closer to home.

As a result, our picture of the Milky Way is constantly changing as technology improves and astronomers learn more about distant galaxies. The current picture is richer than even just a few years ago as astronomers have filled in knowledge gaps and added new details.

They’ve recently learned, for example, that the mysterious dark matter saturating our galaxy is actually “warm,” and they verified by various indirect means the existence of a supermassive black hole at its center. Studies have also shown that the Milky Way is more massive, more crowded and its stars more lonely than previously thought.

If our virtual travelers could then now fly home, approaching the Milky Way from afar and then soar to its center, here is what they would find.

Out there

The galaxy's main disc is surrounded by a halo of old stars and globular clusters (shown in red) in this rendering.

Credit: NASA

Artist's impression of the globular cluster Messier 12 and its tidal tail as it orbits our galaxy.

Credit: ESO

First stop: The halo

The Milky Way is a member of a collection of more than 50 galaxies called the Local Group. In terms of space occupied, Andromeda, or M31, is the biggest galaxy in this posse, but the Milky Way is the most massive.

Were an intergalactic traveler to approach the Milky Way edge-on, the first thing she would notice is a luminous halo made up of gas and stars enveloping the galaxy. The halo is about 100,000 light-years in diameter and 1,000 light-years thick.

A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion km).This halo contains some 170 orbiting star clusters and about a dozen small galaxies. The gravitational tug of the Milky Way is so great that it can sometimes tear these passing satellites apart, stripping them of gas and even stars. One star cluster, Messier 12, is thought to have been robbed of as many as a million stars in this way.

Orphan stars stripped from their parent galaxies and clusters form streamer-like “tidal tails” or else they linger in the galactic halo, where they intermingle with other lone stars. These other stars are mostly ancient, around 12 billion years old and older, and they don’t rotate around the galactic center in any organized way.

Orbiting satellites can also affect the shape of the Milky Way. According to one hypothesis, the strange warp in the Milky Way’s hydrogen disk is caused by the movement of two dwarf galaxies—the Large and Small Magellanic Clouds— and their interactions with dark matter as they orbit our galaxy.

Dark matter is an unknown sort of material that has never been seen. Astronomers know it permeates or galaxy and others because the collections of stars could not hold together without some other, invisible source of gravity.

Next Stop: The spiral disk

Astronomers estimate that the Milky Way contains about 100 billion stars. Recently, however, this number was upped by about a billion after the discovery that very old, nearly invisible stars had escaped earlier detections.

You Are HereThe Milky Way is believed to contain four major spiral arms, all of which start at the galaxy's center, plus a number of smaller arms. Our Sun is located on a spur of the Orion Arm. Credit: NASA/JPL

Most of the Milky Way’s stars are concentrated in a main disk, which lately has been described as a series of disks, none of which are entirely distinct, but instead overlap one another. The largest is known as the thick disk; this disk is fairly flat and spirals like a slow-spinning hurricane because of our galaxy’s rotation.

Nestled within the thick disk is an even flatter disk of stars, known as the thin disk. The stars in this thin disk rotate even faster around the galactic center than those in the thick disk.Further in is yet another disk, known as the extreme disk, where stars and clouds of gas are moving fastest of all.

Our Sun, which is 4.6 billion years old, is located 26,000 light-years away from the galactic center on one of the spiral arms. It is a location considered more suitable than others for harboring life, in part because the central region is too chaotic, and in part because the concentration of metals there is too heavy, and it’s too light in the galaxy’s outer fringes.

The Sun makes one complete orbit around the galaxy about once every 225 million years. In contrast, stars near the galactic center complete a lap in a few million years or less. These stars as a group tend to be younger than the galactic average, most ranging in age from 1 billion to 10 billion years old.

Getting closer: The galactic bar

A galactic traveler nearing the center of the Milky Way will feel a greater pull of gravity as the ship approaches the densest and brightest part of our galaxy, a spherical region known as the central bulge.

The Milky Way BarRendering of the Milky Way and its central bar as it might appear from above. Arrow shows location of our Sun. Credit: NASA/JPL-Caltech/R. Hurt

Things are much different here. Most of our galaxy is relatively uncrowded—the nearest star to our Sun, for example, is 4.2 light-years away. But roughly 10 million stars are known to orbit within a light-year of the galaxy's center.

Recent infrared surveys with NASA’s Spitzer space telescope confirmed that the Milky Way is not a perfect spiral galaxy but instead sports a long bar of stars within the central bulge. This galactic bar is believed to be made up of about 30 million stars, stretching 27,000 light-years from end to end. It consists mainly of old, red stars, which is one reason it stands out and can be detected.

The galactic bar is thought to spin like a propeller inside the Milky Way center, helping to create our galaxy’s unique spiral shape.

Observations of other galaxies also suggest that galactic bars plays an important role in feeding the colossal black holes believed to lay at the heart of many galaxies, including our own.

Destination: The black hole

The Milky Way’s suspected black hole is called Sagittarius A*, or Sgr A*, and is thought to have between 3.2 and 4 million times the mass of our Sun.

Where the Action IsIllustration depicts what might occur very close to Sgr A*. The black hole is surrounded by a disk of gas (yellow and red). Massive stars, in blue, have formed in this disk, while small disks represent where stars are still forming. Credit: NASA/CXC/M. Weiss

Recent studies suggest that all of this mass is confined, amazingly, to an area approximately 10 times smaller than Earth’s orbit around the Sun. Sgr A* is also probably rotating, making one full revolution about every 11 minutes.

Scientists haven’t glimpsed Sgr A* directly but they infer its distance from the incredible speeds of the stars around it, which move 50 times faster than Earth orbits the Sun. The gravity required to keep these stars in such a fast, tight orbit is calculable, and the tiny area into which it must fit indicates that it has to be a black hole, experts say.

While most black holes form from the collapse of massive stars, colossal black holes like Sgr A* are believed to have “co-evolved,” or formed along with the galaxies they inhabit.

According to this view, black holes are more than just indiscriminate and voracious gobblers of matter; they are forces of creation that help sculpt a galaxy’s shape and distribute its stars.Our intergalactic traveler’s journey through the Milky Way ends here at Sgr A*. The ship must either swerve away and make for other galaxies, or risk breaching the black hole’s event horizon, the theoretical boundary beyond which gravity is so strong that no form of matter or energy can escape.

More to come

There are still vital details missing in our picture of the Milky Way. Current models insist, for example, that our galaxy should have as many as a thousand dwarf galaxies buzzing around it, each with between 0.01 percent to 10 percent the mass of the Milky Way. Yet only a relative few satellite galaxies and globular clusters have been found.

Our Messy FutureA simulation of what might happen when the Andromeda Galaxy hits ours. The central regions will collide and merge to form a single elliptical galaxy. Credit: F. Summers/C. Mihos/L. Hemquist

Also, even though astronomers can predict that the Milky Way will collide with Andromeda and cease to be a spiral galaxy in about three billion years, our galaxy’s origins is a story that remains largely untold.

According to the best recent theories, the Milky Way and other large galaxies like it grew through a combination of mergers between small hot clouds of intergalactic matter and, over time, galactic cannibalism.

Like many of the details about our Milky Way uncovered so far, the answer to this mystery will probably be found far from home as well, in young galaxies that are still forming and in distant ones where scientists have found new features thought to be important for galaxy formation and star births.

Pluto is no lone ranger in the farthest expanses of the Solar System — its travelling companions now number three. And if Pluto can have so many, why shouldn't other objects in the distant, icy Kuiper belt?

Once thought to be a solitary denizen of the outer reaches of the Solar System, Pluto — which piqued our curiosity in 1978 with the discovery of its large satellite, Charon1 — is becoming ever more intriguing. In fact, the relative sizes of Pluto and Charon (Charon's diameter of around 1,200 kilometres is just over half that of Pluto's) means they are a 'double planet', orbiting a mutual centre of gravity, or barycentre, outside the surface of Pluto. But the story does not stop there. On page 943 of this issue, Weaver et al.2 present Hubble Space Telescope images showing that the Pluto system is at least quadruple. And as Stern et al. indicate in a companion paper3 on page 946, this complexity portends further discoveries: more small satellites may be lurking out there, and cratering impacts on them may have liberated rings or arcs of matter. Propitiously, NASA's New Horizons mission4, 5 is now successfully launched (Fig. 1) and on its way to a flying visit to Pluto and its companions in 2015.

Figure 1: Destination Pluto.The New Horizons spacecraft took off from Cape Canaveral on 19 January 2006 aboard an Atlas V rocket, bound for the Pluto system. Speedy results are not to be expected: the half-tonne, piano-sized spacecraft must cover a distance of just under five billion kilometres, and will reach a point of closest approach some 10,000 kilometres from Pluto on 14 July 2015.High resolution image and legend (69K)

Following Clyde Tombaugh's discovery of Pluto in 1930, searching for satellites was an obvious first task. But none was found until Pluto's march towards its point of closest approach to the Sun, coupled with the exquisite optics of a ground-based telescope, finally allowed Charon to be pinpointed1. Since then, ground-based surveys6, 7 have yielded no evidence for other satellites larger than about 160 kilometres in diameter. Motivated by the impending launch of New Horizons, Weaver and colleagues2 secured Hubble Space Telescope time in May 2005 to search for satellites as small as around 25 kilometres across8. Sure enough, two objects were found travelling through space with Pluto that had motions consistent with orbits around the Pluto–Charon barycentre (Fig. 2).

Figure 2: A remote quartet.Two Hubble Space Telescope images of the Pluto system taken three days apart, revealing the existence of two smaller satellites, P1 and P2, in addition to Charon (discovered in 1978). P1 is the farther of the two newcomers from the system's centre of gravity, which lies just above the surface of Pluto. It completes just one orbit for every six of Charon's; P2 completes about one-and-a-half in the same time.High resolution image and legend (13K)

This discovery2 prompted a fresh look at Hubble images from 2002 taken to map Pluto's surface. Although these images were not optimized for the identification of satellites, when preliminary orbital calculations gleaned from the 2005 images were added in, the presence of two additional companions was confirmed. The diameters of the satellites, creatively dubbed 'P1' and 'P2' (they will receive their official names later this year), are respectively around 60 and 50 kilometres, assuming surface reflectivities similar to that of Charon. (They are larger if their reflectivities are lower.)

Satisfying as discovery for discovery's sake is, it is the intriguing orbits of the newly spotted satellites that is creating the most scientific excitement. The present, limited data show that P1 and P2 are in circular orbits in the same plane as Charon. Moreover, the radii of their orbits place them in a resonant dance with Charon: for every twelve orbits Charon makes, P1 completes almost exactly two; in the same time, P2 (which is closer in) completes nearly three. Such consonance is not likely if P1 and P2 are captured objects that just happened, once upon a time, to have ventured too close to Pluto: tidal forces from Pluto and Charon are not great enough to coerce captured objects into co-planar resonances over the age of the Solar System3. The most plausible explanation is that Charon, P1 and P2 are all Pluto's progeny, and split off from it through a giant impact3, 9. The disk of material ejected by this collision into orbit around Pluto allowed these satellites — and perhaps others yet unseen — to condense in co-planar, circular orbits3. The resonant niches occupied by P1 and P2 may have been particularly fertile locations for coalescing material, or for maintaining long-term orbital stability.

As Stern and colleagues point out3, implications abound for Pluto's brethren in the Kuiper belt, the disk-shaped region of small, icy bodies found outside the orbit of Neptune. Within current detection limits, up to a fifth of all Kuiper-belt objects seem to have satellites or to be part of a binary system10. Pluto is the first known quadruple system, but multiple companions may be just the tip of the iceberg for the complexities of gravity's play on small bodies far from the perturbative forces of the Sun and giant planets. For example, most ejected debris from cratering impacts on P1 and P2 can easily escape the satellites' surfaces, but not the gravitational hold of the Pluto system. So tenuous rings or ring arcs may be the rule, rather than the exception, for Pluto and other multiple-bodied congregations in the Kuiper belt3. Even quadruple systems may become passé as investigations become increasingly percipient.

Those planning NASA's New Horizons mission, now en route first to a gravity assist from Jupiter in February 2007 and then its July 2015 appointment with Pluto, are now adding to their to-do list highly resolved imaging and spectroscopy of the newly discovered satellites. Refining these satellites' sizes and their orbital positions in nine years' time will also be a priority for observations to follow those currently being reported2. Both on its way in and out of the Pluto system, New Horizons' instruments will canvass the orbit plane for more satellites, rings and other telltale signs that might reveal the origin and evolution of this close-knit family. Pluto is a lonely place no more.

Wednesday, February 15, 2006

U.S. Budget for space exploration is the biggest in the world, far bigger than the E.U. or Japanese budget. The E.U. and Japan do have some good projects for space exploration but the biggest and most valuable ones are financed by the U.S.The decision to scrap key programs such as the exploration of Europa (one of the possible places for life to exist) sounds like a disaster to the science community. Space exploration is inherently slow. It is worse if budgets are scrapped... to finance a far less useful war.

By Wesley T. Huntress Jr. and Louis FriedmanThe Planetary Societyposted: 14 February 200607:15 am ETLet’s put the bottom line right at the top. The Bush administration is unwilling to provide the funds necessary to fulfill its Vision for Space Exploration.

The reasons—whether Iraq, Katrina, or the president didn’t really mean it—don’t matter. The White House wants U.S. obligations to the international space station partners to be honored, the space shuttle flown as many times as necessary to complete the station’s construction, and a replacement for the shuttle (the Crew Exploration Vehicle, or CEV) flying by 2014. All very laudable goals in principle, but not so if the funds are not provided.

The administration has handed these goals to NASA without the funds necessary to accomplish them. NASA’s human spaceflight program was left $3 billion to $5 billion short for flying the desired number of shuttle flights and completing space station construction. This dilemma has forced the NASA administrator to cannibalize the rest of the agency for the money. Last year he tapped aeronautics and technology. This year all that is left to pay the bill is science.

The administration’s 2007 budget proposal removes $3.07 billion from the previously planned five-year run out of the Earth and space science budget. Of this, $2.99 billion is to come from solar system exploration alone — only one of the several science disciplines in NASA and ironically one of the most relevant to human exploration.

This cannot be done without causing serious harm both to robotic exploration and to a space science community that should, and needs to be, a partner with human exploration. As a NASA official once said: “Exploration without science is just tourism.”

In the press conference explaining the budget, officials cited the growth of space science in NASA from about 21 percent of the budget in 1992, to 32 percent today. But, during that same time period, space science has been carrying the agency exploration flag, and the agency has been rightly proud of the productivity of the Earth and space sciences. Missions such as Hubble, Mars Exploration Rovers and Cassini/Huygens are indeed, as NASA Administrator Mike Griffin himself said, the “crown jewels” of NASA.

Griffin vowed never to transfer “one thin dime” from scientific exploration into human spaceflight. He has been forced to renege on that promise. Now, in the administration’s fiscal year 2007 budget request, we have a sudden, wrenching decision to flat-line science, and no soft landing has been provided.

There are to be many delays in science flight programs and many “deferrals beyond the budget horizon” (read cancellation) in others. It’s a long list and you will hear about them all soon enough. There is even to be more “rebalancing” of the Mars program, most of whose growth was removed last year. Missions, technology development and research aimed at Mars exploration have been reduced and eliminated, proving that the agency has all but abandoned the vision’s Mars goal for human spaceflight.

NASA needs reminding that the vision is not just about human spaceflight. The very first goal stated in the vision is to “implement a sustained and affordable human and robotic program to explore the solar system and beyond.” The vision further advocates that we “conduct robotic exploration across the solar system for scientific purposes and to support human exploration.”

But as bad the mission delays and deletions are, this budget proposal makes a full frontal attack on basic science. It proposes to cut NASA’s Earth and space science research grant programs by 15 percent across the board. Astrobiology, NASA’s newest and most innovative research program, is targeted for a 50-percent cut. And all cuts are immediate—today, in the 2006 budget year. Grants are to be reduced immediately, dimming the prospects of many young, motivated students. What kind of message is that to the best and brightest of America’s hopes for a rich technological future? Ironically, this comes days after the president called for increased spending on the physical sciences.

These research programs make NASA’s flight missions possible and turn raw data into discoveries. Without them, the missions are just engineering exercises. The excuse for this unprecedented cut is that since the flight programs are being delayed and deferred, we don’t need the research. Would it have made sense in 1905 to tell Einstein to stop his research and go flip burgers just because we don’t need relativity right now?

A mission loss affects a few institutions, a few scientists and a few congressional districts. But an across-the-board reduction in research grants hurts every Earth and space scientist in the country. These stakeholders reside mostly in universities in a large percentage of congressional districts in the nation. Mission losses aside, this is an assured way to alienate the science community just when its support is so urgently needed.

NASA appears desperate to preserve the illusion of the vision. The administrator’s budget message said about the vision, “we will go as we can afford to pay.” But the administration won’t pay, and NASA is going forward anyway even when they can’t afford to pay for it—by gutting science and robotic exploration. Who will be led to the budget guillotine next year when development costs rise in human spaceflight or if the shuttle suffers more problems?

Wesley T. Huntress, Jr. is president of The Planetary Society and director of the Geophysical Laboratory at Carnegie Institution of Washington; he is the former NASA associate administrator for Space Science. Louis Friedman is executive director of The Planetary Society. He was former congressional science fellow of the Senate Committee on Commerce, Science and Transportation. If you agree with this article, join the Planetary Society's NASA 2007 Budget Letter Writing Campaign

Tuesday, February 14, 2006

Altruistic Love Related to Happier Marriages - LiveScience

By Robert Roy BrittLiveScience Managing Editorposted: 09 February 200606:42 am ETAltruism may breed better marriages, a new study suggests. Or, the data might mean that good marriages make people more altruistic.

Whatever, altruism and happiness seem to go together in the realm of love.

"Altruistic love was associated with greater happiness in general and especially with more marital happiness," concludes Tom Smith of the National Opinion Research Center at the University of Chicago in a report released today.

I do

Study participants were asked whether they agreed with statements that define altruism, such as, "I'd rather suffer myself than let the one I love suffer," and "I'm willing to sacrifice my own wishes to let the one I love achieve his or hers."

Those who agreed with the statements tended to also report happiness with their spouses.

Among the more altruistic, 67 percent rated their own marriage as "very happy." Among those who were profiled as the least altruistic, only 50 percent said they were very happy in marriage.

And here's one for those of you who're still waiting for your partner to commit: Forty percent of the married people ranked near the top for altruistic responses, while only 20 percent of those who had never married did so. The divorced and separated came in at around 25 percent.

The study asked dozens of questions to gauge both altruistic intentions and behaviors. How often do you give blood? Do you return money when a cashier makes a mistake in your favor?

Rising altruism

In a separate finding, Smith looked at a similar study from 2002 and found that altruistic feelings are on the rise. The number of people having "tender, concerned feelings toward the less fortunate" rose 5 percent, to 75 percent.

Smith speculated why:

"People have been suffering more negative life events than in the past and as such there is greater need for caring and assistance," he said. "Likewise, there is greater disparity between the rich and the poor with the lot of the former, but not of the latter, improving in recent years."It's not known if altruism begets a good marriage or vice versa.

But Smith said connection between romantic love and altruistic behavior probably comes from an appreciation of love developed in a healthy marriage and reflects the connection between marriage and love in general, which is part of the teachings of many religions.

The study found that people who pray every day performed, on average, 77 acts of altruism a year vs. 60 for those who never pray.

Men vs. women

Altruistic love scores were higher for women who are homemakers than women who work outside the home. Men scored higher than women. "This may be because there is an element of heroic stoicism and being a protector," Smith writes in the report.

Altruism runs higher among older people and those with college educations.

Smith also analyzed empathy, described as feeling protective of others or concerned for the less fortunate. Some of the findings:

--> Women have a greater feeling of empathy than men.--> Children from two-parent homes are more empathetic.--> Girls raised by a single father are the least likely to develop empathy--> Financial status bears little on altruism or empathy.--> People who vote are more empathetic and altruistic. --> Empathy is higher among those who fear crime. --> Empathy is higher among those who support increased spending on social programs.

The research was based on data from in-home surveys conducted every two years with support from the National Science Foundation. Smith used data from the 2004 survey, of 1,329 adults, and compared it to the 2002 results.

The Near Earth Asteroids offer both threat and promise. They present the threat of planetary impact with regional or global disaster. And they also offer the promise of resources to support humanity's long-term prosperity on Earth, and our movement into space and the solar system.

The technologies needed to return asteroidal resources to Earth Orbit (and thus catalyze our colonization of space) will also enable the deflection of at least some of the impact-threat objects.

We should develop these technologies, with all due speed!

Development and operation of future in-orbit infrastructure (for example, orbital hotels, satellite solar power stations, earth-moon transport node satellites, zero-g manufacturing facilities) will require large masses of materials for construction, shielding, and ballast; and also large quantities of propellant for station-keeping and orbit-change maneuvers, and for fuelling craft departing for lunar or interplanetary destinations.

Spectroscopic studies suggest, and ‘ground-truth' chemical assays of meteorites confirm, that a wide range of resources are present in asteroids and comets, including nickel-iron metal, silicate minerals, semiconductor and platinum group metals, water, bituminous hydrocarbons, and trapped or frozen gases including carbon dioxide and ammonia.

As one startling pointer to the unexpected riches in asteroids, many stony and stony-iron meteorites contain Platinum Group Metals at grades of up to 100 ppm (or 100 grams per ton). Operating open pit platinum and gold mines in South Africa and elsewhere mine ores of grade 5 to 10 ppm, so grades of 10 to 20 times higher would be regarded as spectacular if available in quantity, on Earth.

Water is an obvious first, and key, potential product from asteroid mines, as it could be used for return trip propulsion via steam rocket.

About 10% of Near-Earth Asteroids are energetically more accessible (easier to get to) than the Moon (i.e. under 6 km/s from LEO), and a substantial minority of these have return-to-Earth transfer orbit injection delta-v's of only 1 to 2 km/s.

Return of resources from some of these NEAs to low or high earth orbit may therefore be competitive versus earth-sourced supplies.

Our knowledge of asteroids and comets has expanded dramatically in the last ten years, with images and spectra of asteroids and comets from flybys, rendezvous, and impacts (for example asteroids Gaspra, Ida, Mathilde, the vast image collection from Eros, Itokawa, and others; comets Halley, Borrelly, Tempel-1, and Wild-2. And radar images of asteroids Toutatis, Castalia, Geographos, Kleopatra, Golevka and other... These images show extraordinary variations in structure, strength, porosity, surface features.

The total number of identified NEAs has increased from about 300 to more than 3,000 in the period 1995 to 2005.

The most accessible group of NEAs for resource recovery is a subset of the Potentially Hazardous Asteroids (PHAs). These are bodies (about 770 now discovered) which approach to within 7.5 million km of earth orbit. The smaller subset of those with orbits which are earth-orbit-grazing give intermittently very low delta-v return opportunities (that is it is easy velocity wise to return to Earth).

These are also the bodies which humanity should want to learn about in terms of surface properties and strength so as to plan deflection missions, in case we should ever find one on a collision course with us.

Professor John Lewis has pointed out (in Mining the Sky) that the resources of the solar system (the most accessible of which being those in the NEAs) can permanently support in first-world comfort some quadrillion people. In other words, the resources of the solar system are essentially infinite… And they are there for us to use, to invest consciousness into the universe, no less. It's time for humankind to come out of its shell, and begin to grow!!

So both for species protection and for the expansion of humanity into the solar system, we need to characterize these objects and learn how to mine and manage them.

Once we learn how to work on, handle, and modify the orbits of small near-earth objects, we will have achieved, as a species, both the capability to access the vast resources of the asteroids, and also the capability to protect our planet from identified collision threats.

Since the competing source of raw materials is "delivery by launch from Earth," which imposes a launch cost per kilogram presently above $10,000 per kg, this same figure represents the upper bound of what recovered asteroidal material would be presently worth in low earth orbit.

Future large scale economic activity in orbit is unlikely to develop however until launch cost drops to something in the range $500 to $1,000 per kilogram to LEO. At that point, any demand for material in orbit which can be satisfied at equal or lower cost by resources recovered from asteroids, will confer on these asteroidal resources an equivalent value as ore in true mining engineering terms, i.e., that which can be mined, have valuable product recovered from it, to be sold for a profit. Now, $500,000 per ton product is extraordinarily valuable, and is certainly worth chasing!

Note that the asteroidal materials we are talking about are, simply, water, nickel-iron metal, hydrocarbons, and silicate rock. Purified, and made available in low earth orbit, they will be worth something like $500,000 per ton, by virtue of having avoided terrestrial gravity's "launch cost levy."

These are values up there with optical glass, doped semiconductors, specialty isotopes for research or medicine, diamonds, some pharmaceuticals, illicit drugs. On the mining scene, the only metal which has ever been so valuable was radium, which in the 1920's reached the fabulous value of $200,000 per gram!

Platinum Group Metals (which are present in metallic and silicate asteroids, as proved by the "ground truth" of meteorite finds) have a value presently in the order of $1,000 per ounce or $30 per gram. Vastly expanded use in catalysts and for fuel cells will enhance their value, and PGM recovery from asteroid impact sites on the Moon is the basis of Dennis Wingo's book, "Moonrush."

When will we see asteroid mining start? Well, it will only become viable once the human-presence commercial in-orbit economy takes off. Only then will there be a market. And that can only happen after NASA ceases acting as a near-monopolist launch provider and thwarter of competition, and reverts to being a customer instead.

A developing in-space economy will build the technical capability to access NEAs, almost automatically. And regardless of the legal arguments about mineral claims in outer space, once the first resource recovery mission is successful, what's the bets on a surge in interest similar to the dotcom-boom and biotech-boom?

The first successful venturers will develop immense proprietary knowledge, and make a mint. And some as-yet unidentified (but almost certainly already discovered) NEAs will be the company-making mines of the 21st century.

Mark Sonter is an independent scientific consultant working in the Australian mining and metallurgical industries, providing advice on radiation protection, industrial hygiene, safety, and remediation of radioactively contaminated sites. His career includes 2 years as a high school science teacher, 6 years as a University Physics lecturer in Papua New Guinea, postgraduate studies in medical physics, and 28 years in uranium mining radiation safety management, including 5 years as Corporate Safety Manager for a major mining corporation. Mark was a visiting scholar at U of Arizona in 1995, and during 1995-97 wrote a research thesis on the Technical and Economic Feasibility of Mining the Near-Earth Asteroids. He was granted funding by the Foundation for International Non-governmental Development of Space (FINDS) to develop concepts for mining the near-Earth asteroids. He can be reached atsontermj@tpg.com.au.

NOTE: The views of this article are the author’s and do not reflect the policies of the National Space Society.

Thursday, February 09, 2006

Tyrannosaurs get a father figure - Nature

Fossil hunters find the first Jurassic specimen of this fearsome family.Michael Hopkin

Ask any dinner-party palaeontologist and they'll tell you that, despite its star turn in Jurassic Park, Tyrannosaurus rex didn't live in the Jurassic period. But now a team in China has found a tyrannousaur that did, and it gives us valuable clues about the rise of this clan of prehistoric predators.

The new species, found in Xinjiang province in northwestern China, lived around 160 million years ago. This makes it more than twice as old as T. rex, and the most primitive known member of the family.

At just 3 metres long, the creature is a small relative of T. rex, which could reach a mighty 13 metres. But its gaping, beak-like face armed with teeth, and its powerful legs, show that it too would have been a ferocious killer.

The dinosaur's discoverers, led by Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, have named it Guanlong wucaii - meaning 'crested dragon from the five colours'. The name comes from the huge nasal crest on the creature's head, and the fact that it was found in a region of China characterized by many-coloured rocks. The team describes the find in this week's Nature1.

Rare vintage

Dinosaur specimens of this vintage are rare, says Mark Norell, who is based at the American Museum of Natural History in New York and is part of the team who studied the find. Most other Jurassic dinosaur fossils have been unearthed in the Americas. "This fills in a big blank about tyrannosaurs," he says. "With samples from only one continent, you don't have a good picture."

The presence of a nasal crest is particularly interesting, says Norell, because it is so similar to the head ornaments carried by many of today's birds. Both birds and carnivorous dinosaurs such as tyrannosaurs belong to the evolutionary family known as the theropods.

The crest of G. wucaii probably functioned as a signal, either to attract potential mates or for species recognition. "It would not have been used for fighting - it would have been paper-thin," Norell says.

If it was a sexual ornament, it might imply that this individual was a male. But if it was for species recognition, that would leave the dinosaur's sex in the balance, and determining sex using bones alone is tricky. "That's still a long way ahead," says Norell.

Tuesday, February 07, 2006

NASA is battling accusations that it tried to stifle its top climatologist, a man well known for speaking his mind about the causes and consequences of global warming.

James E. Hansen, the director of the New York-based Goddard Institute for Space Studies (GISS), and several of his NASA associates contend that political appointees at the agency's headquarters here have demanded to review his lectures and papers in advance, and have senior agency managers stand in for him in interviews with journalists. Hansen said in a Feb. 2 interview with Space News that the restrictions were imposed following a speech he gave at the American Geophysical Union's annual meeting in early December.

During that speech, Hansen said that the growth in greenhouse gas emissions needed to be halted by 2025 in order to avoid a "grim scenario" involving a shrinking arctic and rising sea levels. Hansen's speech attracted widespread media attention and was excerpted by the International Herald Tribune and The New York Review of Books as commentaries.

Hansen's most recent concerns were reported in an article published by The New York Times Nov. 29. The New York Times story prompted House Science Committee Chairman Sherwood Boehlert (R-NY) to write NASA Administrator Mike Griffin the following business day demanding an explanation.

"NASA is clearly doing something wrong, given the sense of intimidation felt by Dr. Hansen and others who work with him," Boehlert wrote. "Even if this sense is a result of a misinterpretation of NASA policies - and more seems to be at play here - the problem still must be corrected."

The House Science Committee's senior Democrat, Rep. Bart Gordon (Tenn.), sent Griffin a similar letter.

Dean Acosta, NASA deputy assistant administrator for public affairs, said the agency has imposed no new restrictions on Hansen, but only contacted the Goddard Institute to remind public affairs personnel there that media interviews needed to be coordinated with headquarters. Acosta said in a Feb. 2 interview the event that prompted headquarters staff to contact Hansen's institute was not the American Geophysical Union speech, but an ABC News story quoting Hansen that caught the agency by surprise when it ran in mid-December.

"NASA is committed to open and full communications," Acosta said. "Our policy - which is similar to that of any other federal agency, corporation or news organization - is that any NASA employee speaking on the record, issuing a press release or posting information on our Web site, must coordinate such activities with the Office of Public Affairs. No exceptions.

"It's not saying you have to get approval," Acosta added. "It's just saying you have to coordinate to make sure we are not stepping all over ourselves."

"That's a partial backing off of what they were demanding," Hansen said in a Feb. 2 telephone interview with Space News. Hansen said NASA headquarters public affairs officials did not contact him directly, but spoke to the Goddard Institute's communications liaison, Leslie McCarthy.

Also contacted by headquarters public affairs around the same time was Mark Hess, the public affairs chief at NASA's Goddard Space Flight Center. The Greenbelt, Md.-based field center oversees Hansen's New York-based institute.

In a Dec. 19 e-mail to Hansen's Goddard-based supervisors, Franco Einaudi and Laurie Leshin, Hess referenced separate conversations he and McCarthy had with Acosta and NASA Assistant Administrator for Public Affairs David Mould concerning the ABC News story and the release of Hansen's annual global temperature analysis, which showed that 2005 was the hottest year since records started being kept in the late 1800s.

"Leslie is putting together a note which recaps what HQs [sic] has directed (not asked) us to do with regard to 'monitoring' the work of [the Goddard Institute for Space Studies] and Dr. Hansen in particular," Hess wrote. "I think we need to discuss this with you because I don't feel that in some instances, some of what they are asking us to do falls into the [Goddard Space Flight Center] to [Science Mission Directorate] reporting chain, not public affairs (e.g. they are asking we keep track of his schedule, his speaking engagements, his media interviews, all the science papers being submitted from GISS, all the content on the GISS Web site, etc., etc.)"

The next day, Hess sent Acosta and Mould an e-mail summarizing the "PAO procedures" that Hess and McCarthy planned to go over with Hansen per Acosta and Mould's directions.

Among these procedures, according to Hess's e-mail, were forwarding interview requests for Goddard Institute employees to headquarters public affairs where NASA Associate Administrator for Science Mary Cleave and her deputy Colleen Hartman would be given "right of first refusal on all interview requests."

Acosta said that neither he nor Mould received a copy of that e-mail when it was sent, but that he has since been provided with a copy.

Now that he has seen it, Acosta said it is "pretty consistent" with NASA's public affairs policy, except, he said, where it talks about giving Cleave and Hartman the right of first refusal on interview requests.

"When you get into [the part about] Mary Cleave and Colleen Hartman, obviously Jim Hansen is under their organization," Acosta said. "The mission directorate leadership certainly has the prerogative to designate who they feel are the appropriate spokespeople on a subject matter."

Hansen said he was not averse to letting headquarters know when he has an interview coming up, or even letting others such as Cleave and Hartman do the interview about broader NASA science issues.

"That would be very reasonable except when someone knows they want to talk to me," Hansen said. "Unless they don't trust me as a spokesman to speak to the media, then they should tell me. But what is it they don't like about me? That I don't know what I'm talking about? That I'm not a good scientist?"

David Goldston, the House Science Committee's staff director, said Feb. 2 that NASA had been cooperating with Boehlert's inquiry, but that more work remained.

"We're still trying to get to the bottom of what's going on. We certainly do not think this is something Mike Griffin was trying to impose, but we do think something is amiss and it's not solely a matter of Jim Hansen resisting reasonable bureaucratic procedures."

Acosta, for his part, suggested that the current controversy boils down to Hansen not wanting to comply with established public affairs policy.

"I think it is clearly that somebody doesn't agree with the policy in place," Acosta said.Acosta also said that Hansen has clashed with NASA's public affairs procedures before then claimed that he was being asked to abide by more restrictions than other agency employees. "This is the same scenario that has come from him for the past 20 years," Acosta said.

Hansen gave a speech at the University of Iowa in October 2004 in which he said government scientists were being prevented from speaking freely on global warming and that he intended to vote for President George W. Bush's Democratic challenger, Sen. John Kerry (Mass.). When NASA officials discouraged him from making the speech, Hansen told his story to reporters then traveled to the Iowa engagement at his own expense.

Hansen, who described himself as "a middle-of-the-road conservative," told Space News he did not regret telling the Iowa audience who he intended to vote for. "I actually said if he were on the ballot I would prefer to vote for [Arizona Republican] John McCain, but then I rationalized [backing Kerry] on the climate issue and said we have to take stronger action," Hansen said.

Hansen said he sees himself first and foremost as a scientist and has no desire to trade the life of the quantitative researcher for that of the activist.

"I have no intention of being a Steve Schneider-type person who spends his time talking about climate impact or climate policy," Hansen said. Schneider is the often-quoted Stanford University climate scientist who achieved notoriety for telling Discover magazine in a 1989 interview that climatologists wanting to get their point across to an indifferent public needed "to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have" about the causes and consequences of global warming.

Hansen said that as the director of one of the United States' three premiere climate-modeling centers, he has an obligation to speak out about what the data say about globally warming.

"The NASA mission statement says 'to understand and protect our home planet'," Hansen said. "If I didn't speak out on this issue I wouldn't be doing my job."

Saturday, February 04, 2006

What price must be paid for free speech? - Times

What a shame that some Europeans see in these cartoons a form of "freedom of expression".Insulting someone or a community is different from expressing a point of view.Considering these insults to be acceptable will only bring an end to any form of communication between communities. Is that what is meant by "freedom"?

I have seen these cartoons. They are shockingly rude. They clearly imply that Islam = terrorism. They clearly imply that ALL muslims in that sense should feel guilty for being muslims. If this is not insulting, I wonder what is.Let us consider that these cartoons were equally insulting the jewish communities. Wouldn't the whole Western world be willing to stop any form of antisemitism to be spread in the Media?

The great debate gathered pace over a remarkable week on whether the right to express a view - whatever the cost in terms of damage to racial and religious harmony - must be defended without question

ANDREW ROBERTS, historian“I have seen the cartoons and was unimpressed by them. They are the intellectual equivalent equivalent of shouting “fire” in a crowded cinema. While there is a need for a genuine discussion about the rights of the West to define its own boundaries of free speech, these cartoons are trite, purposely provocative and unnecessary. In this case, the protesting Muslims have a point.“Western civilisation loses out if these insulting images are the best critique that we can make. But I would point out that many Muslims, particularly in the Arab world, would have a stronger argument in favour of censorship if they began to withdraw the anti-Jewish, and occasionally antiChristian, cartoons that often appear in their own newspapers.”NI_MPU('middle');

TARIQ MODOOD, Professor of Sociology, Politics and Public Policy at the University of Bristol“This week Parliament, supported by the liberal intelligentsia, decided that religious hatred was a lesser problem than racial hatred and could be effectively dealt with by weaker legislation. Events in the world are testing this view. While some want to demonstrate their right to provoke religious people, others want to demonstrate their right to be provoked. The ideal that there might be a culture of mutual respect looks forlorn, but are we also to give up on the second best of conflict-avoidance?“In any case, satire should check the powerful, not hurt the powerless. The underlying causes of the Muslim anger is a deep sense that they are not respected, that they and their most cherished feelings are ‘fair game’.”

PETER BROOKES, Times cartoonist“I only saw the drawings yesterday. My first reaction was ‘what feeble cartoons’. Perhaps I don’t understand Danish humour, but there was only one out of the 12 — where Muhammad’s turban seems to be a bomb — that seemed to have any meaning.“But even that one is a poor cartoon. It is ambivalent. You can read it one of two ways: either terrorism is using the cloak of Islam, is dressing itself as Muhammad, or that Muhammad himself is a terrorist. I hate that ambivalence in a cartoon, not knowing quite what the message is. We could be misreading the intentions of the artist entirely.“There is an awful duality about cartoonists: on the one hand, we feel we must be able to depict anything, we must be free. So as a rule, I try not to be too sensitive about these things, and all cartoonists are guilty of doing things when we have no idea what the reaction is going to be.“And yet, as a cartoonist, I think there has to be a purpose. I cannot see any reason for these images; they just seem gratuitous. They are meaningless. Depicting Islam, there is no need to show the Prophet.“Of course now there is so much happening, everything is moving so fast, that this looks like it will all go on and on. And, ironically, we will have to do cartoons about it.”

ZIAUDDIN SARDAR, author of Desperately Seeking Paradise: The Journey of a Sceptical Muslim“I have spent a lifetime criticising Islam and Muslims, but I am absolutely infuriated by these cartoons. They are a provocative and premeditated insult against Islam, and a violent abuse of power. What people must remember is that we are watching the repetition of an argument that took place in Europe during the Thirties. Then, we were discussing the right to depict Jews in cartoons with racial stereotypes. Now, we are discussing the right to show Muslims.”

ROGER SCRUTON, philosopher“People of different religions or none can co-exist — so we hope, and so we have reason to believe. But co-existence with someone requires respect for the icons, rituals and symbols of his faith.“It is as wrong to mock the religious taboos of a Muslim as it is to pour scorn on the icons of Christianity. Unfortunately, because we have got used to the continual childish blasphemy against the Christian faith that passes for sophistication in the film industry, on television and in the art schools, we think that others, whose experience of Western society is more recent and who are not yet inoculated against its hooligan iconoclasm, will also respond with a saddened shrug when people pour scorn on their faith.“We have so lost the habit of respect for sacred things that we are astonished to discover that others can still be devastated by public acts of desecration. This kind of blasphemy is not a form of free speech, any more than pornography is. On the contrary, it is the kind of behaviour that makes free speech impossible.”

A.C. GRAYLING, philosopher“Free speech is the fundamental civil liberty. Without it none of the others is possible. I applaud the newspapers in Europe that have shown solidarity with Denmark’s Jyllands-Posten newspaper by reprinting the cartoons, and regard our own Foreign Secretary as pusillanimous in buckling to the artificially inflated hysteria of those who think that feeling offended gives them a licence to censor other people’s freedom to criticise and satirise whomever they wish.”

MICHAEL FRAYN, author“I am strongly in favour of freedom to comment on anything, including religious matters. There needs to be some possibility to protect not only from direct incitement but from things that lead indirectly to violence. I think the spread of falsehood that can incite fear and hatred is something that should be controlled. I think people should be perfectly free to caricature any aspect of religion they wish. I am always baffled as to why it is considered blasphemous. It is made clear in Islam that Muhammad is not a divine figure. He is a human figure.”

NI_MPU('middle');TONY BENN, former minister“People’s faith should be respected. To say anything that offends against the faith of others is a real mistake. (The cartoons) have caused great offence at a very sensitive time. This is not a question of illegality; that is nonsense. You just do not insult people.”

THE RIGHT REV RICHARD HARRIES, the Bishop of Oxford“Those newspapers that have decided not to print the cartoons at this time have acted wisely and in the public good. Freedom of speech is fundamental to our society and all religions need to be open to criticism.“But this freedom needs to be exercised responsibly with a sensitivity to cultural differences. Respect for the deeply held convictions of others as well as freedom of speech is the mark of a civilised society.”

SIR JONATHAN SACKS, Chief Rabbi“Never before have we lived so closely with people whose cultures and sensitivities are so different from our own. It is as if the whole lexicon of anthropology has come to life and we are living in the middle of it.“Many schools I visit have children from as many as 40 or 50 different countries. And the children I meet have a wisdom that sometimes we adults lack. They feel enlarged, not threatened, by diversity. They know not to assault someone else’s deeply held convictions.“Like the Christians of my childhood, they know that each of us cares deeply about something but not the same thing; and they try to respect that fact. Civilisation needs civility. Judaism says that putting someone to shame is like bloodshed. At the end of every prayer we pray, we ask God to guard our tongue from evil.”

IBRAHIM MOGRA, senior member of the Muslim Council of Britain“Muslims are upset, distraught and angry. I am urging them to calm down and take stock of their own lives. We should all remain within the law and not be provoked by hot-heads on both sides. Muslims take seriously the Koranic injunctions to listen to the Prophet and not to be forward in the presence of God or his messenger.“Because of these teachings it is very easy for Muslims to feel hurt and pain when such an important person is villified in this manner. Most Muslims believe Muhammad’s teachings were primarily about living in peace and harmony with the rest of the world. So to depict him as a terrorist is deeply distressing.”

DR ANTHONY SELDON, Master of Wellington College“Something that is grossly offensive to another culture has to be taken into account. It is completely wrong to make it a principle of freedom because in any free society you have to accept that others have taboos. The absolute principle exists the other way round too. Muslims can make expressions of horror or contempt or injury clear, but they are guilty of the same intolerance if they make physical threats on other people.”

SHAHID MALIK, Labour MP“A bit of self-discipline is what is needed. In my view, in this country we are at least two decades ahead of some of our partners in Europe on the issues of integration, minority communities, race and religion. I have spoken in many of these countries and I am truly horrified. There is no better place in Europe than Britain to be Muslim.“But Muslims will be feeling today as if they are the new Jews of Europe. It is ironic that some of the cartoon caricatures reprinted in the German newspapers are similar to some of the ones used to depict Judaism and Jews in the 1930s. The point is that publications have run with this story not from the traditional news perspective but from some kind of macho media statement about freedom of expression”

PHILIP PULLMAN, author“Religions are keen to assure us that God will punish wickedness in ways even more ingenious and extensive than human beings can devise; if blasphemy is obnoxious to the Almighty, the best response of his human followers is surely to rub their hands with glee at the thought of what will come to the blasphemers in due course, and not seek to pre-empt God’s judgment with human laws.”

Thursday, February 02, 2006

Concern Grows over Kama Sutra Computer Virus - PC Magazine

Total posts: 1By Michael Kahn, ReutersSAN FRANCISCO—A destructive worm posing as a pornographic e-mail may already have infected hundreds of thousands of computers and could erase many everyday files on Feb. 3, security experts warned on Tuesday.

The "Kama Sutra" worm, which targets popular Microsoft Corp., Adobe Systems Inc. and ZIP files, is a threat because many users will not know the virus has infected their computers until it is too late, security experts said.They also estimate that the worm—which spreads by e-mailing itself to addresses in an infected computer's mailbox—may already have slipped onto 275,000 to 500,000 machines and is now simply waiting to obliterate files on Friday.The virus, also known as Grew.A or MyWife, tricks users by appearing as an e-mail attachment with subject lines such as "Hot Movie," "give me a kiss" and "Miss Lebanon 2006."Some variations refer to the ancient Kama Sutra guide to elaborate sexual positions in order to attract attention and convince victims to open."It claims to be a movie or picture with some sort of sexual content," said Johannes Ullrich, chief research officer at the nonprofit SANS Institute research group. "That is how it tricks you."The virus causes a keyboard and mouse to freeze up and then disables anti-virus programs when the computer is restarted, leaving a machine vulnerable, said Ken Dunham, rapid response director at VeriSign Corp.'s security unit iDefense. The attack is scheduled to begin at midnight on Feb. 3.The virus mainly has infected computers of vulnerable consumers and small businesses, which are far less likely to have up-to-date security software, he said.The Kama Sutra worm also stands out because its primary purpose is to destroy files rather than to seek financial gain or to take control of a computer, security experts said.Dunham said any users who suspect they may have triggered the worm should reinstall an anti-virus program and make sure the virus has been removed."It is already under way and will be activated unless people get removal tools," he said. "If you have opened an e-mail and your computer froze up, you should be very concerned."Copyright Reuters 2006. All rights reserved. Users may download and print extracts of content from this website for their own personal and non-commercial use only. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters and the Reuters sphere logo are registered trademarks or trademarks of the Reuters group of companies around the world.

Debunking "supernatural" claims: James Randi - Wilkepedia

Randi (born Randall James Hamilton Zwinge, August 7,1928 in Toronto, Canada), more often known as The Amazing Randi, is a stage magician, a skeptic, best known as a debunker of pseudoscience. He is perhaps most known for the One Million Dollar Paranormal Challenge, in which his James Randi Educational Foundation will award a prize of one million USD to anyone who is able to show evidence of any paranormal, supernatural, or occult power or event, under test conditions agreed to by both parties. He is also a regular on a television program called Bullshit!, which is hosted by noted skeptics Penn & Teller.His interest in debunking the paranormal started when he was in his early teens. He was present at the show of a magician who asked for someone in the audience to help him with his performance. Randi of course wanted to do that, having started with magic tricks himself. When the young Randi raised his hand, the magician said, "Ah, young man, you're a magician yourself, aren't you?", much to Randi's amazement. After the show, Randi approached the man and asked how he knew this. The man told Randi he didn't. It was simply part of his routine and whenever he turned out to be right, he'd credit his "magical powers" and whenever he was wrong, he'd turn it into a standard quip he had.He also witnessed many tricks that were presented as being of a supernatural nature. One of his earliest reported experiences is that of seeing an evangelist using the "one-ahead" routine to convince churchgoers of his divine powers.

Comment sent to the magazine Nature

I am very disappointed with the IAU.

Yet, I understand there is a revolution underway. The scientific communauty needs to acknowledge that the "essence" of a Planet is too be massive enough to be round-shaped. Historically, the astronomers used to study planets movements in the sky only. Now that the technology is so advanced, the scientific communauty needs to stick to simple rules.This mighty new "space object" deserves more than being called a "KBU". As a planet, it will attract enough attention from the public to justify massive space exploration programs to explore it.

An object discovered earlier this year and considered by some to be our solar system’s 10th planet is indeed larger than Pluto, a new study confirms.

The object, catalogued as 2003 UB313, is by many accounts a planet. It is round and orbits the Sun.

But because several other objects meet those criteria and also approach Pluto’s size, astronomers have been wrangling for months over how to define the word “planet.” It is not known if or when the International Astronomical Union, which rules on such things, will issue a decision. Members of an advisory board weighing the issue can’t even agree on the parameters of a definition.

Meanwhile, 2003 UB313 is now known to be about 1,860 miles (3,000 kilometers) in diameter, give or take 190 miles (300 kilometers).

Pluto is 1,430 miles (2,300 kilometers) wide.

The object’s size was initially calculated based on an estimate of how much sunlight it reflects. But astronomers don’t know exactly what its surface is made of, so they could not be sure how reflective it is.

The new study, led by Frank Bertoldi from the University of Bonn, relies on new observation of 2003 UB313’s thermal emission. The calculations are based on the object’s size and its surface temperature, which can be estimated based on the object’s distance from the Sun.

The results are detailed in the Feb. 2 issue of the journal Nature.

"Since UB313 is decidedly larger than Pluto," Bertoldi said, "it is now increasingly hard to justify calling Pluto a planet if UB313 is not also given this status."

But 2003 UB313 is much farther away. Its elongated orbit takes it far out into the icy Kuiper Belt, twice as far from the Sun as Pluto. Many astronomers now say Pluto is a Kuiper Belt Object and should never have been called a planet.

So if 2003 UB313 is termed a planet, as some suggest, then a handful of other good-sized, round worlds known to exist—and perhaps hundreds yet to be found in the Kuiper Belt—would also have to be called planets. Among the other candidates: Sedna, which is about three-fourths as large as Pluto, 2004 DW and Quaoar.

One suggestion is to call the outer worlds “dwarf planets.”

Scott Sheppard of the Carnegie Institute of Washington takes this view:

“Whichever way you care to count them, with the discovery and measurement of the size of 2003 UB313 there are no longer nine major planets in the solar system,” Sheppard writes in an analysis for Nature.

Sheppard also notes a surprise that’s come from this study and others recently.

Astronomers have now accurately measured the diameter and reflectiveness, or albedo, of a handful of Kuiper Belt Objects.

“It seems that the largest objects have the highest albedos,” Sheppard said. “This could be because gravity on these objects is large enough for them to have active atmospheres and so be able to retain volatile gaseous substances that could brighten their surfaces.”

Large size of 2003 UB313 fuels debate over what is and isn't a planet.Mark Peplow

The recently discovered 'tenth planet' of our Solar System is substantially larger than Pluto, astronomers have found.

For many, the discovery that object 2003 UB313 is about 3,000 kilometres across will remove any doubt that it deserves to be called a planet.

"Since UB313 is decidedly larger than Pluto, it is now increasingly hard to justify calling Pluto a planet if UB313 is not also given this status," says Frank Bertoldi, an astronomer at the Max Planck Institute for Radioastronomy in Bonn, Germany, and part of the team that reveals UB313's size in this week's Nature1.

When astronomer Mike Brown of the California Institute of Technology in Pasadena unveiled 2003 UB313 to the world in July 2005, his team was already confident that the new object was at least as large as Pluto, and deserved the status of 'planet'.

But UB313's elongated orbit takes it almost twice as far away from the Sun as Pluto ever gets, making it very difficult to measure its diameter precisely. One clue to its larger size came from the fact that it is slightly brighter than Pluto; a larger mirror would reflect more of the Sun's light. But an alternative explanation could have been that UB313 is simply made of a more reflective material than Pluto.

Ice maiden

Using the Institute for Millimetre Radio Astronomy (IRAM) 30-metre telescope in Spain, Bertoldi's team has now studied the radiowaves coming from UB313, which reveal how much of the Sun's rays are absorbed and re-radiated as heat. Because very little reflected sunlight is emitted at these wavelengths, the object's brightness in radiowaves depends only on its size and surface temperature.

Based on its enormous distance from the Sun, UB313 is calculated to be tremendously cold: a staggering -248 °C. Bertoldi and his colleagues combined this value with their measurements of UB313's radiation to determine its reflectivity and size.

Although this first estimate of 3,000 kilometres may be out by as much as 400 kilometres, this still puts UB313 well ahead of 2,300-kilometre-wide Pluto in the size stakes, making it the largest body found in the Solar System since the discovery of Neptune in 1846.

The research also shows that UB313 has a reflectivity, or albedo, of about 60%. This is roughly the same as Pluto's, suggesting that the two objects' surfaces are made of very similar materials, such as frozen methane and nitrogen snow. Only a very frosty world could produce an albedo of 60%, says Brown.

How does the 'tenth planet' measure up against other bits of the Solar System? Click here to find out.

Brown has also been trying to measure the size of UB313 by using the Hubble Space Telescope. Although he released preliminary findings on 25 January at a public meeting at Foothill College in Los Altos Hill, California, suggesting that UB313 was just a few percent larger than Pluto, he now says that measurement is wrong. "It was an extremely preliminary estimate," he explains.

A planet with no name

2003 UB313 is not the catchiest name, but unfortunately this temporary designation will have to stick until the International Astronomical Union (IAU) decides whether it is indeed a planet that warrants a name from classical mythology.

Since 1992, more than 1,000 similar, albeit smaller, objects have been found in the region around Pluto known as the Kuiper Belt, and astronomers estimate that there may be more than half a million still waiting to be discovered. As more of these icy remnants from the Solar System's birth turn up, Pluto blends into the crowd and its claim to be a unique planet grows slimmer and slimmer.

Some astronomers argue that Pluto should be stripped of its title, to become a Kuiper Belt Object like its orbital fellows. Others suggest that anything larger than Pluto found in the outskirts of the Solar System should also be called a 'planet', which would include UB313. "I'd prefer to keep Pluto as a planet, for historical reasons," says Bertoldi.

The IAU set up a committee of 19 top astronomers to come up with a workable definition for a planet that would rule UB313 in or out, but in November 2005 the group finally admitted defeat after failing to reach a clear consensus. The IAU has promised action later this year, but Brown is already impatient. "Imagine how you'd feel if your baby didn't have a name for seven months," he says.